Synchronized machine gun for airplanes



may w23. 1,454,137

Q. A. R055 SYNCHRONIZED MACHINE GUN FOR AIPLANES Filed Sepi. 14 191.8

ma@ oz Patented May 8, 1923.

PATENT OFFICE.

OSCAR A. ROSS, OF NEW YORK, N. Y.

SYNCHRONIZED MACHINE GUN' FOR AIRPLANES.

Application led September 14, 1918. Serial No. 254,154.

To all whom t may concern Be it known that I, OSCAR A. Ross, a citizen of the United States of America, residing at 154 West 57th Street, New York city, in the county of New York and State of New York, have invented a new and useful Improvement in Synchronized Machine Guns for Airplanes, of which the following is a specification.

My invention belongs to that class which pertains to synchronized machine guns on airplanes and has for its more prominent object the attainment of the results in a more eicient and economical manner.

. It is a well known fact that airplane ropellers operates at 1200 to 1500 revolutions per minute, and, assuming that a shot from a synchronized machine gun could be fired at each one half revolution, a total of 2400 to 3000 shots per minute could be red. However, single barrel machine guns, as at present manufactured, do not, to the best of my knowledge and belief, -permit such rapid firing, in fact many of them cannot 25 successfully fire a single shot for each complete revolution of the propeller blade operating at normal speed.

Further, inasmuch as the periodicity of re-loading of the machine guns is constant, and that of the ropeller revolutions varies, it will be seen that the interval of time between shots may be increased due to the fact, that as that part of the synchronizing mechanism belonging to the airplane motor may have completed its function calling for discharge of the machine gunjust before the said gun had completed its reloading operation, and therefore, the engine must complete another cycle 'before the shot is tired.

@ne aim of my invention is to overcome the above diiculties whereby. not only can one shot be successfully fired during each one half revolution of the propeller, but. if required. two or more such shots may be red during this interval. The decided advantage of such a condition is obvious when it is considered that a veritable hail of bullets can be discharged at the opportune moment and in a very small .period of time.

It is obvious that after an airplane operator has properly sighted his gun on an adversary, the one remaining requirement is to shower him with bullets, and it is obvious that this must be done in a very short space of time as both airplanes are moving rapidly. My invention accomplishes these results and at the same time permits the machine guns to perform their reloading cycles at a normal rate of speed, and, in addition allows -an interval of time for cooling of their barrels before firing subsequent shots.

All the above and other aims sought and attained will be evident as the description of one embodiment of my invention, as shown by the accompanying drawing, progresses. and in which, Fig. 1, is a partial diagrammatic and partial plan view of my invention as applied to an airplane, and, Fig. 2, is an enlarged view taken on line A-A of Fig. 1, and. Fig. 3, is a diagrammatic view illustrating the synchronism of the machine guns with the airplanes propeller blade.

None of the various parts employed are, or need be` of any special form or construction. but for a more ready understanding of my invention 'and its operation a prellminary description may be apposite.

Mounted in airplane 1, of any well known construction is motor 2, having the usual propeller 3. Motor 2, as shown, is assumed to be of the overhead cam shaft type having cam shaft 4, extending rearwardly and on which are mounted the cams 5 and 6. Mounted above motor 2, and arranged to fire within the circumferential range of propeller 3, are machine guns 7. V8, 9, and 10, having operating magnets 11, 12, 13, and 14. Arranged in the pathpof cam 5, are contact fingers 15, and lnormally impinging against stops 17. and 18. but adapted` when moved by cam 5, to contact with fixed contact posts 19, and 20. Arranged in the path of cam 6, are contact fingers 21, and 22. normally impinging against stops 23, and 24. but adapted. when moved by cam 6. to contact with fixed contact posts 25, and 26.

Battery 27, of any preferred form, as for example, storage, supplies electric energy for the several circuits as follows ircwit #1.

From battery 27, to wire 28, push button 43, wires 29, and 30, magnet 14, wire 31, contact post 19, contact finger 15, wires 32, and 42 to battery 27. I

Utrcuz't #52.

From battery 27, wire 28, push button 43, wires 29 and 33, magnet 12, wire 34, contact post 26, contact finger 22, wires 35 and 42, returning to battery 27.

Circuit #3.

From battery 27, wire 28, push button 43, wires 29 and 36, magnet 11, wire 37, contact post 20, contact finger 16, wires 38 and 42, returning to battery 27.

From battery 27, to wire 28, push button 43, wires ,29 and 39, magnet 13, wire 40, contact post 25, contact finger 21, wires 41, and 42 returning to battery 27.

The operation of my invention is as follows -After the operator of the airplane, to which guns as 7, 8, 9, and 10, are attached, has obtained a line of sight on an adversary, push button or switch 43 is op-v erated to close the circuit between wires 28 and 29. Assuming the cams to be in the position as shown by Figure 2, circuit #1, will b e closed through contacts 15 and 19, and magnet 14, energized, thereby causing core 46, through rod 47, to fire machine gun 10.

As shaft 4, rotates in the direction as indicated by arrow 48, cam 5, passes away from contact finger 15, thereby allowing said finger to return against stop 17, in this manner opening circuit #1.

After shaft 4 has made substantially a 90 degree movement, cam 6 will engage with finger 22, causing it to contact with contact post 26. This action, assuming button 43 is still depressed, closes circuit #2,there-` by energizing magnet #12, and causing firing of'machine gun 8.

In the same manner, after shaft 4 has revolved 180 degrees, cam 5 will engage with finger 16, closing circuit #3, causing gun #7 to be fired.

Likewise, after shaft 4 has revolved 270 degrees, cam 6 will engage with finger 21, closing circuit #4, and gun #9, will be fired.

Assuming that cam shaft 4 revolves at one half the speed of the crankshaft 50, to

' which propeller 3 is attached, and as is quite customary with airplane motors, guns 10, 8, 7, and 9, will be fired in the succession named each time the propeller 3 assumcs a position as represented substantially by line B--B of Figure 3. By such synchronizino' two shots are fired for each revolution ofj the crankshaft 50.

Assume however, that shaft 4 was caused to revolve at the same speed as crankshaft 50. Under such circumstances the cams as 5 and 6 would be placed at substantially 45 degrees from the position shown in Figure 2, and under which condition gun 10 would fire when the propeller was substantially on a line represented by C-C of Figure 3, and gun 8 after said propeller had assumed a plane substantially on a line D-D, or in other words had travelled 90 degrees. After said propeller has revolved 180 degrees and is again substantially on the line C--C, gun 7 will fire, and, after position D-D is again reached gun 9 will fire. By such synchronizing four shots are fired for each revolution of the crankshaft, or two for each one half revolution of the propeller.

From the foregoing it will be evident that by varying the location of cams as 5 and 6, on shaft 4, and by changing said shaft ratio of revolution with respect to that of crankshaft 50, one or more machine guns may be fired after a propeller blade has passed and before a succeeding blade has interfered with the range of said guns.

It will be obvious to those versed in the art that various modifications may be made without departing from the spirit of my invention, and therefore I do not limit myself to the exact form and construction as shown but claim,

1. An airplane, a motor therefor, having a propeller driven thereby, a plurality of machine guns mounted on said airplane and adapted to fire between the blades of said propeller, means actuated by said motor for firing each one of. said guns in a given sequence in synchronism with said propeller blades and a plurality of the guns during the time elapsing between the passing of a given point by one propeller blade and the passing of the same point by another propeller blade.

2. A machine gun fire control system comprising in combination with an aerial propeller and a plurality of machine guns mounted to fire between the revolving blades thereof, separate electromagnetic means for controlling the firing of each of said guns, circuit connections for each of said guns and a source of current associated with said electromagnetic means, and a contact device having separate contacts each timed in accordance with the speed of said propeller for operatingr the circuits of each respective gun so that firing may occur only when said blades are out of line of fire of the respective guns.

3. Amachine gun fire control system comprising in combination with an aerial prosaid blades are out of line of fire of the peller and a plurality of machine guns respective guns. mounted to re between the revolving blades In testimony whereof, OSCAR A. Ross has l0 thereof, means actuated in accordance with signed his name to this speciicatiomthis 5 the speed of said propellers for firing any 4th day of September, 1918.

and al1 of said guns in a predetermined sequence, so that firing may occur only when OSCAR A. ROSS. 

